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Author Topic: backup power for a sewage pump?  (Read 8468 times)

europachris

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backup power for a sewage pump?
« on: August 28, 2006, 03:08:39 PM »
I have a small dilemma I need to solve.   How do I run a small (1/3 or 1/2 hp) sewage pump during power outages?  Basically, I think a UPS of somesort is required?  Do they have backup systems for existing sump pumps rather than the battery powered backup systems?

Our house has a downstairs bathroom in the basement.  It drains into a sealed crock along with the basement floor drain.  It then pumps up the water a few feet to the level of the line to the septic tank.

Well, the other day we had 4-1/2 inches of rain in a few hours.  Well, the wife went into the basement with bare feet and found a good size wet spot on the carpet by the closet where the pump is located.  Evidently at some point the power went out and there was water filling this crock somehow.  I do know that the water line and power line for the well pump leak where they pass through the poured foundation during very heavy rains.  I've tried to seal these with little results.  But, they are right by the floor drain so it's not a big issue.

I can only surmise that in the period the power was out that the crock overfilled and ran out on the floor.  I vacuumed up a gallon or two of water, and put the dehumidifier on the carpet to dry it out.  We don't use the bathroom for anything but hand washing and dog washing in the tub, and also the floor drain and water softener drain into this system, so it wasn't (fortuntately) full of sewage.

I need an automatic backup as we weren't home at the time to fire up the generator.  The pump only runs for a few seconds to empty the crock, so the power (kWh) requirements are very low. 

I also have a proper sump pump for the basement drainage, but it's dry as a bone at all times.

Thanks!

Chris



bitsnpieces1

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Re: backup power for a sewage pump?
« Reply #1 on: August 28, 2006, 04:39:35 PM »
  Other than a UPS, an engine driven generator or engine driven pump I'm not sure.  It sounds like you have two seperate sumps(crocks) so you might see if you could pipe the shower one to the other via gravity drain.  That's assuming there is a difference in height. 
  I don't know what you've tried to seal the water pump lines, but, you might try digging out the concrete around the lines, say a 1/2 inch around and 1 - 2 inches deep and then filling with a silicone sealant worked well into the space. 
Lister Petter AC1, Listeroid 12/1, Briggs & Stratton ZZ, various US Mil. surplus engines. Crosley (American) 4cyl marine engine(26hp).

europachris

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Re: backup power for a sewage pump?
« Reply #2 on: August 28, 2006, 04:50:37 PM »
It is a sealed crock (for the most part) but it's not totally water tight. 

I really don't know where this water came from, except the leakage into the floor drain which drains into this crock.  The power wasn't out for more than a few minutes as far as I can tell, but it was enough....

I can't see if the water might have come in through the basement itself, but it doesn't look like it did.

I can only surmise that it somehow overflowed while the power was out and it was raining extremely hard.

Some sort of deep cycle battery and UPS type power controller would be a piece of cake to install, if I could just find the right one.

Chris

bitsnpieces1

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Re: backup power for a sewage pump?
« Reply #3 on: August 28, 2006, 05:25:13 PM »
  I don't think the small hp pumps need real clean AC, so maybe one of the car/truck inverters for power tools would work instead of an more expensive UPS.  You might be able to size it to just run the pump by itself (most efficient use). 

  You also might check to see if the water flowed backwards out of the discharge pipe while the power was off.  It's checkvalve might be stuck open and the pump is cycling a bunch.  If you have a Kill_A_Watt plug the pump into it for a while and see if it's running a lot of time. 
Lister Petter AC1, Listeroid 12/1, Briggs & Stratton ZZ, various US Mil. surplus engines. Crosley (American) 4cyl marine engine(26hp).

Tugger

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Re: backup power for a sewage pump?
« Reply #4 on: August 28, 2006, 09:19:29 PM »
Sometimes the contractor will run the floor drain and tee it into the drains for your evestrough...when the water can't flow out fast enough it will back up the floor drain...there is a backflow preventer floor drain available at your local plumbing supplier...

http://www.femyers.com/products/sse/sse_mbsp.html
back up system

Doug

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Re: backup power for a sewage pump?
« Reply #5 on: August 30, 2006, 02:32:18 AM »
Europachris I use a 15 year old Sendon brand 400W square wave UPS to run my 1/4 hp sump pump. I added close to 100 AH of external batteries with a low voltage pick up and secondary charger ( cheap 30 amp dc rated relay and an Omron S82k 24Vdc power suply with a dropping resistor for current limiting .5 amp). the batteries are divided into four banks with 10 amp Potter Brumfield CBs ( small yes but they never trip and it give me the option to issolate a section or two if I want to save them in an extended blackout and turn the UPS on and off when needed ).  The unit still has it internal battery,  I think its an 18 AH gell cell. This give me about 12 hours back up with a 15-20 % duty cycle and its lasted for years. I just noticed yesturday I need to clean my terminals but thats all its needed since I put it together durring the black out of 03.
The pump doesn't like the harmonics but starts and runs without hot ( about 30 seconds a pump cycle )

Doug

rleonard

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Re: backup power for a sewage pump?
« Reply #6 on: August 30, 2006, 07:32:17 PM »
I have had a water powered backup sump pump for years.  It always works!  No battery to ever fuss with. 

http://www.zoeller.com/zcopump/products/backupsystems/homeguard.htm

Bob
Faster - Better - Cheaper  You can have any two, but not all three

europachris

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Re: backup power for a sewage pump?
« Reply #7 on: August 30, 2006, 08:55:39 PM »
I have had a water powered backup sump pump for years.  It always works!  No battery to ever fuss with. 

http://www.zoeller.com/zcopump/products/backupsystems/homeguard.htm

Bob


Hey, that's really sweet!  Only problem I have is that it'll only work during a blackout as long as the well tank has pressure, which won't be long with much of a draw on it.

Chris

rgroves

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Re: backup power for a sewage pump?
« Reply #8 on: August 30, 2006, 09:15:58 PM »
This sounds like a job for a bilge pump. High flow, low head, short cycles.  Likely the water will be fairly clean (no big chunks)
Any marine store will have them in a bunch of sizes, and they're likely to have a float switch to turn them on and off. Bilge pumps work up to about 10 feet of head.
Then all you need is a little bank of 12 VDC and you're ready. 
No need for an inverter.

rg
A country boy can survive - Hank Williams Jr.

timgunn1962

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Re: backup power for a sewage pump?
« Reply #9 on: September 19, 2006, 08:40:17 PM »
If you can live with the limited backup time, I'd say this sounds like a job for a UPS. As has been pointed out, you don't need a particularly good waveform, so anything big enough and cheap enough should do fine. I have found that it is usually a lot cheaper to buy a bigger UPS with standard batteries than a smaller UPS with extended runtime batteries, particularly second-hand. A cheap off-line type of at least 1000VA should be fine and would give at least 30 min of pump runtime with a 1/2 HP pump. Back-up time on no load would probably be well over 2 hours. A runtime chart for the APC SmartUPS range can be found at http://www.apc.com/products/runtime_for_extendedruntime.cfm?upsfamily=165

It is some time since I ran a UPS from a generator. We had to use a very expensive on-line type (made by Galatrek in the UK, local for us) with the intelligence to ignore the deviation from a perfect mains-frequency waveform. Trying to run anything else meant that the UPS was in near-permanent battery mode as it saw the frequency changes as the generator speed controller did its thing, interpreted them as mains failures and switched into back-up mode. I understand the APC "smartUPS" range (line interactive), among others, has adjustable sensitivity to allow operation on generators. Limited experience suggests that, while a big improvement, it is not a complete solution. The only testing I did was on a cheap gas-powered generator of about 5 kVA. You may find your generator has better speed control and does not cause a problem.

Personally, I would look for a second-hand smartUPS between 1000 and 2200 VA and take it out of circuit anytime I ran the generator.

If you don't feel you could live with the limited backup time, it is probably worthwhile going with the 12V pump and battery bank, someone suggested. With 12V switches and without the burden of running an inverter, either stand-alone or in a UPS, you would have a potential standby time of weeks without needing a huge battery bank.